Ships Drives

[rust2]

In any event, regardless of the drive types, it seems to be accepted by most that maneuver drives operate under many of the same principles as reaction drives, with the primary difference being they have little to no exhaust (of if they do, it's not like a true reaction drive). So the engines are generally going to be in the rear of the ship pushing it forward, or perhaps located on sponsoons (like Serenity from Firefly).

Yes, this is how I see it.

 

[alex_greene]

The visible light emerging from reactionless drives, for example the light being emitted from the outlets of impulse engines in Star Trek's starships or the long light strips in the stern of the Millennium Falcon in Star Wars or the ridiculously-shaped Destiny in Stargate Universe could well be a sort of EM radiation emission - radiated IR heat, coupled with a harmless visible light radiation which could be a byproduct of the thrust process like Cernenkov radiation. Perhaps this harmless visible light emission could go by a name such as Miller radiation in the technical journals, and the thrust itself could be described as an "asymmetric coaxial Miller thrust field" in the scientific literature.

I dunno, for all we know the Miller drive (how about that - you can still call them M-drives!) pushes against the nearest gravimetric distortion, such as a planet, or against the fabric of the universe itself; and the universe pushes back, producing thrust and acceleration. The byproduct of the universe pushing back is M-radiation from the thruster exhaust plates in the stern.

And lo!, with a wave of the hand, an explanation is born. One, possibly, of many.

MWM, pbuh, would be so proud.

 

[fusor]

MWM, pbuh, would be so proud.

Or nauseated.

 

[Reynard]

The explanation has been for a long time the drive pushes and pulls against gravity wells and the weak and strong nuclear forces in a true reactionless manner. Been in several editions. Word of Mark. No glowy particles or energy bleeds.

By the way, the Haynes series of Owner's Workshop Manuals list the Star Trek Impulse engine as fusion reaction chambers expelling superheated deuterium plasma. Definitely a reaction drive. The common Star Wars sublight engine, such as on the Millennium Falcon, is also a fusion reaction releasing charged particles. They are also listed as illegal to use in an atmosphere because of the radioactivity. The secondary repulsorlift (antigrav)/landing jets system are for atmospheric flight and landings. Why does that sound so familiar?!

So Traveller went a different route after Classic with true science fictiony reactionless drives.

 

[Tenacious-Techhunter]

If an RPG system isn’t making those fictional technologies in it as simple to the players as an ICE is to a car mechanic, it’s failing those players; because the players need to use that technology every bit as bad as the mechanic does.

This is where I think you miss the difference between the real world physics and the use of fictional physics in a roleplaying game. The players do not have to use the fictional technology at all, they do not have to repair gravitic engines and so on, they only have to describe the use of the fictional technology, and for this purpose the technology and the physics behind it can remain a "black box". The players only need to know what this "black box" does, not how it does it and what is inside - while this may be important for you, it is rather irrelevant for the majority of players, mainly because for them it does not provide any additional fun, and fun -and fun only - is why people play roleplaying games.

Yes, but that’s not what Traveller does.

You can’t take a Maneuver Drive out of a Starship and apply it to whatever maneuver-based purpose you might try.

You can’t jury-rig a string of Vehicle Fusion Power Units of a known Wattage into a temporary Starship Power Plant.

These things are not components as you yourself describe them. Which lies at the very heart of my point!

 

[Tenacious-Techhunter]

In any event, regardless of the drive types, it seems to be accepted by most that maneuver drives operate under many of the same principles as reaction drives, with the primary difference being they have little to no exhaust (of if they do, it's not like a true reaction drive). So the engines are generally going to be in the rear of the ship pushing it forward, or perhaps located on sponsoons (like Serenity from Firefly).

If they are on gimballed arms, then it would indeed be possible to swing them forwards, dorsally, ventrally, or to the rear and provide thrust. Though Traveller doesn't take that sort of agility into account, so the issue would be relatively moot beyond aesthetics.

No, the primary difference between Reaction Drives and Reactionless Drives is that Reaction Drives have practical limits, and Reactionless Drives are doomsday weapons.

Additionally, there is no reason to conclude that a Reactionless Drive is pushing the ship, or pulling the ship, or anything of the sort. It depends on how that particular Reaction Drive works.

 

[Tenacious-Techhunter]

The visible light emerging from reactionless drives, for example the light being emitted from the outlets of impulse engines in Star Trek's starships or the long light strips in the stern of the Millennium Falcon in Star Wars or the ridiculously-shaped Destiny in Stargate Universe could well be a sort of EM radiation emission - radiated IR heat, coupled with a harmless visible light radiation which could be a byproduct of the thrust process like Cernenkov radiation. Perhaps this harmless visible light emission could go by a name such as Miller radiation in the technical journals, and the thrust itself could be described as an "asymmetric coaxial Miller thrust field" in the scientific literature.

I dunno, for all we know the Miller drive (how about that - you can still call them M-drives!) pushes against the nearest gravimetric distortion, such as a planet, or against the fabric of the universe itself; and the universe pushes back, producing thrust and acceleration. The byproduct of the universe pushing back is M-radiation from the thruster exhaust plates in the stern.

And lo!, with a wave of the hand, an explanation is born. One, possibly, of many.

MWM, pbuh, would be so proud.

Now you’re just making up nonsense to avoid doing legitimate research on the subject. That’s how we got into this mess in the first place.

 

[Tenacious-Techhunter]

The explanation has been for a long time the drive pushes and pulls against gravity wells and the weak and strong nuclear forces in a true reactionless manner. Been in several editions. Word of Mark. No glowy particles or energy bleeds.

By the way, the Haynes series of Owner's Workshop Manuals list the Star Trek Impulse engine as fusion reaction chambers expelling superheated deuterium plasma. Definitely a reaction drive. The common Star Wars sublight engine, such as on the Millennium Falcon, is also a fusion reaction releasing charged particles. They are also listed as illegal to use in an atmosphere because of the radioactivity. The secondary repulsorlift (antigrav)/landing jets system are for atmospheric flight and landings. Why does that sound so familiar?!

So Traveller went a different route after Classic with true science fictiony reactionless drives.

Yup. A race to the bottom down the slippery slope.

 

[Sigtrygg]

You can’t take a Maneuver Drive out of a Starship and apply it to whatever maneuver-based purpose you might try.

The characters in game can if they need to and if they have the skills and equipment to do so.

You can’t jury-rig a string of Vehicle Fusion Power Units of a known Wattage into a temporary Starship Power Plant.

The characters in game can if they need to and if they have the skills and equipment to do so.
By the way I have actually had this happen in games.

These things are not components as you yourself describe them. Which lies at the very heart of my point!

It allows different referees to describe the way the sci-fi works in their universe.
All you need is a bit of imagination and a few rules tweaks if necessary.

 

[Tenacious-Techhunter]

You can’t take a Maneuver Drive out of a Starship and apply it to whatever maneuver-based purpose you might try.

The characters in game can if they need to and if they have the skills and equipment to do so.

Not as-written they can’t.

You can’t jury-rig a string of Vehicle Fusion Power Units of a known Wattage into a temporary Starship Power Plant.

The characters in game can if they need to and if they have the skills and equipment to do so.
By the way I have actually had this happen in games.

Not as-written you can’t.

These things are not components as you yourself describe them. Which lies at the very heart of my point!

It allows different referees to describe the way the sci-fi works in their universe.
All you need is a bit of imagination and a few rules tweaks if necessary.

That’s my point. Right there. It becomes a war of imagination between the GM and the Players, or the Players amongst themselves, or the GM against the table’s resident Rules Lawyer. It destroys games. Instead of just defining these things so that “Ship’s Engineer” characters and “Gadgeteer” characters can just use them, the burden is placed entirely upon the GM to rule on something characterized entirely by flowery language. It’s just bad. Why play a character with knowledge about technology if your use of technology is constrained entirely by how well a GM interprets flowery words? That’s like trying to play a character who is good at throwing random improvised objects, but all the sizes and weights of common objects are described by symbolic poetry.

 

[Sigtrygg]

Not as-written they can’t.

And where is it written?

Not as-written you can’t.

And where is it written?

That’s my point. Right there. It becomes a war of imagination between the GM and the Players, or the Players amongst themselves, or the GM against the table’s resident Rules Lawyer. It destroys games. Instead of just defining these things so that “Ship’s Engineer” characters and “Gadgeteer” characters can just use them, the burden is placed entirely upon the GM to rule on something characterized entirely by flowery language. It’s just bad. Why play a character with knowledge about technology if your use of technology is constrained entirely by how well a GM interprets flowery words? That’s like trying to play a character who is good at throwing random improvised objects, but all the sizes and weights of common objects are described by symbolic poetry.

The referee defines these things for his/her setting - that's the way it was in the early days of CT and that is the way it still is now.

MGT has a reactionless gravitic maneuver drive - do we know how it works? No.

It also offers a reaction drive complementary/alternative - do we know how it works? No

Do I know how they work in my various campaigns - yes.

 

[MongooseMatt]

That’s my point. Right there. It becomes a war of imagination between the GM and the Players,

We call it storytelling, and it is absolutely the ref's job. The specifics of an M-drive is well within the ref's management - we are certainly not going to give a specific, scientifically-grounded explanation for them. That really would be counter to the game.

Guys, after having read through this thread, I am still not exactly clear why an argument has erupted over this, but please take it down a notch.

 

[Reynard]

We also wonder why T-T is so desperate too. Then again, it's argument for the sake of argument on EVERY subject. If nothing else, the rest of us brush up on our Debating(Tenacious-Techhunter) skill. I think we've all earned a +1 by now.

 

[phavoc]

No, the primary difference between Reaction Drives and Reactionless Drives is that Reaction Drives have practical limits, and Reactionless Drives are doomsday weapons.

Additionally, there is no reason to conclude that a Reactionless Drive is pushing the ship, or pulling the ship, or anything of the sort. It depends on how that particular Reaction Drive works.

Aside from the fact that your view on the basic mechanics of propulsion in Traveller works puts you in a distinct minority, where are you getting a reactionless drive is "a doomsday" weapon?

And if, for the sake of your argument, we accept that at face value, it would nearly ensure that planets would prohibit starships from ever landing on a planet due to their inherent deadly capabilities from their maneuver drive. How do you justify hundreds of "doomsday" vehicles landing and taking off daily from the primary starport, let alone all the other spaceports a high tech industrialized planet is going to have?

So before I call bullshit on that, I'd like to hear where you are getting the information to make that assumption.

 

[theodis]

That’s my point. Right there. It becomes a war of imagination between the GM and the Players,

We call it storytelling, and it is absolutely the ref's job.

On the table, the word of the GM is law. It's that simple. There is no "war".

 

[PsiTraveller]

Just to veer the topic into the use of ship's drives as doomsday weapons I want to ask how you would handle this.
Getting a ship into a system, heading out into the deep, turning around and heading back in and building up speed and turning the ship into a fast moving weapon is a pretty good tactic.

Heinlein used it in "The Moon is a Harsh Mistress", Weber used it as a threat in "Flag in Exile" *.

Could it be adapted to Mongoose? M-Drives may move a ship, but then the ship may stop when the M-Drive does. This would mean no acceleration is imparted, just motion. I have to admit some fuzziness on this point because ship's combat not getting into delta v's of ships and the near impossibility of getting a matching velocity so you could fight.

Reaction Drives could work, if you had enough fuel. Accelerating an iceteroid might work. You may want to plate it over first to protect it.

Anyone used a man made asteroid as a weapon in a game? Or a kamikaze ship at Thrust 9 as a kinetic device?

 

[rust2]

Anyone used a man made asteroid as a weapon in a game? Or a kamikaze ship at Thrust 9 as a kinetic device?

While there have been many discussions about asteroids and starships as kinetic weapons in Traveller, especially about RKKVs (Relativistic Kinetic Kill Vehicles), I do not remember any case where this kind of weapon was actually used in a campaign. However, I have no doubt that someone did it.

 

[AndrewW]

Heinlein used it in "The Moon is a Harsh Mistress"

The rebels didn't need a ship,l all they had to do was thrown rocks 'down' at Earth.

 

[fusor]

Could it be adapted to Mongoose? M-Drives may move a ship, but then the ship may stop when the M-Drive does. This would mean no acceleration is imparted, just motion. I have to admit some fuzziness on this point because ship's combat not getting into delta v's of ships and the near impossibility of getting a matching velocity so you could fight.

It wouldn't just "stop" - as you say, there wouldn't be more acceleration, but the velocity it's built up while the drive was on would still be there. Just point the ship at the planet, put power into the Thruster Plates (fuel is irrelevant, since it's a fusion power plant), watch the devastation from a distance. A week's acceleration at 1g would build up a velocity of about 6 km/s (you'd need about 2 billion km run-up though to get that fast though)

Reaction Drives could work, if you had enough fuel. Accelerating an iceteroid might work.

In most cases you wouldn't have enough fuel.

But this strand of argument really is a huge can of worms that has been argued over many times before without resolution.

 

[theodis]

]
Aside from the fact that your view on the basic mechanics of propulsion in Traveller works puts you in a distinct minority, where are you getting a reactionless drive is "a doomsday" weapon?

And if, for the sake of your argument, we accept that at face value, it would nearly ensure that planets would prohibit starships from ever landing on a planet due to their inherent deadly capabilities from their maneuver drive. How do you justify hundreds of "doomsday" vehicles landing and taking off daily from the primary starport, let alone all the other spaceports a high tech industrialized planet is going to have?

So before I call bullshit on that, I'd like to hear where you are getting the information to make that assumption.

Actually, he has a point here. The physics behind that fact are explained at great length on Winchell Chung's "Atomic Rocket" site http://www.projectrho.com/public_html/rocket/index.php Just read under the topic "reactionless drives". There also was a large discussion on the Traveller Mailing List about 20 years ago. It basically boils down to this: Having no need for reaction mass, a reactionless drive - any reactionless drive - can accelerate forever, provided there is energy. So you just strap a thruster plate, some solar panels and an RTG on a rock, accelerate for a year or so at 1G (or 10 years at 0.1G - it really doesn't matter) and you have a relativistic kill impactor. That's a "Planet Cracker Done Real Cheap" and was/is a great concern among the old Traveller grognards and the more scientifically inclined SF authors.